The present invention relates to substrates which provide one or more optical images which vary according to the angle of view in dependence upon microscopic reflection as opposed to diffraction.
There are many applications where such optically variable images are required or desirable: one important application is to provide a security identification on an article of value. Generally hitherto, relatively complicated methods of manufacture have been necessary in order to produce optically variable images, or alternatively these images have been of poor quality or relatively easy to counterfeit.
We have now devised substrates which provide an optically variable image of good quality, yet these substrates can be formed with a complex array of pixels which make them very difficult to counterfeit.